size | 易学教程

Size of empty Java String

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问题 I heard a colleague say that I would pay "24 bytes" if I dropped a String member in a Java class, even if the String is empty. Is that accurate? Is it the same for Integer, Float, Double? (as opposed to int, float, double, which would be only 4, 4 and 8 bytes each). 回答1: You'll pay 4 or 8 bytes for the reference . Whether you'll pay for an extra object per instance of your "container" object depends on how you get your empty string. For example, if you use the literal "" then all the

Get window size with php [closed]

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问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 6 years ago . What is the problem this code: $window_width= '<script>screen.availWidth</script>'; $window_height= '<script>screen.availHeight</script>'; any idea? 回答1: Nothing wrong in your code, but you can't get any values in PHP variable, because PHP is Server side scripting language. You need JavaScript, not PHP. var

Get window size with php [closed]

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How many elements are full in a C array

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问题 If you have an array in C, how can you find out how much of it is filled? 回答1: In a C array, any element is an object. It's not like in Java where you have references that first have to be assigned to point to objects. Anything in C behaves like a primitive type in Java. If you have an array of pointers in C, you may view this similar to how things in Java work. You can use null pointers to designate "is not filled to point to an object": // creates an array of 10 pointers, and initializes

[20170612]FOR ALL COLUMNS SIZE repeat(11g).txt

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[20170612]FOR ALL COLUMNS SIZE repeat(11g).txt --//昨天看了https://jonathanlewis.wordpress.com/2017/06/01/histogram-upgrade-2/,提到了直方图的问题, --//特别是FOR ALL COLUMNS SIZE repeat引起的问题,在一些特殊情况要注意. 1.环境: SCOTT@book> @ &r/ver1 PORT_STRING VERSION BANNER ------------------------------ -------------- -------------------------------------------------------------------------------- x86_64/Linux 2.4.xx 11.2.0.4.0 Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production create table t (id number,pad varchar2(20),flag varchar2(1)); insert into t select rownum,lpad('a',20,'a') ,'a' from dual

Reduce jar file size

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问题 Is there any way to reduce jar file size? I want a tool that reduces the unused dependencies. I use maven for dependency management. 回答1: A JAR file doesn't normally contain dependencies in the Maven sense. So you must be talking about: a WAR or EAR or similar file, a so-called UberJAR file produced by combining lots of JAR files; e.g. using the Maven shade plugin, or dependencies at a finer granularity than Maven modules. In the first two cases, you can keep out nominally dependent JARs by

Changing Console Window's size throws ArgumentOutOfRangeException

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问题 I am trying to set the size of the Console Window in a c# console application. I get an ArgumentOutOfRangeException with this message: The value must be less than the console's current maximum window size of 41 in that dimension. Note that this value depends on screen resolution and the console font. I am using this to set it: Console.WindowHeight = 480; How do you set the Console window's size properly? 回答1: From MSDN of Console.WindowHeight property: The height of the console window

How does “sizeof” work in this helper for determining array size?

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问题 I've found this article that brings up the following template and a macro for getting array size: template<typename Type, size_t Size> char ( &ArraySizeHelper(Type( &Array )[Size]) )[Size]; #define _countof(Array) sizeof(ArraySizeHelper(Array)) and I find the following part totally unclear. sizeof is applied to a function declaration. I'd expect the result to be "size of function pointer". Why does it obtain "size of return value" instead? 回答1: template<typename Type, size_t Size> char (

I need very big array length(size) in C#

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问题 public double[] result = new double[ ??? ]; I am storing results and total number of the results are bigger than the 2,147,483,647 which is max int32. I tried biginteger, ulong etc. but all of them gave me errors. How can I extend the size of the array that can store > 50,147,483,647 results (double) inside it? Thanks... 回答1: An array of 2,147,483,648 double s will occupy 16GB of memory. For some people, that's not a big deal. I've got servers that won't even bother to hit the page file if I

Is there any way to store unsigned long in core data?

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问题 CoreData provides Integer 16, Integer 32 and Integer 64 storage, but doesn't support any sign qualifiers. You can store an unsigned int (32 bit) as a signed long (64 bit) and make sure the value is preserved for the full range, but an unsigned long seems to require a 128 bit signed integer to store, which of course isn't supported by CoreData. Is there any way then to store unsigned long in coreData? 回答1: [Previous comment promoted to answer] Sounds like it is the bit pattern which is